Device for cleaning the electrode section of an ignition plug



April 1,1969 RYOICH'I MORI v 3,435,561

DEVICE FOR CLEANING THE ELECTRODE SECTION OF AN IGNITION PLUG Filed Dec. 21. 1966 r Sheet of a 1 i i )W /16 12G\'- \12 i 1; l1! '1 M :f q--. 14 29 i2"'* Q; ,2? 11'*\ 0 f I @1 I O Q #2 2 1 i i I i I E L i V INVENTOR. BY g April 1, 1969 RYOICHI Mom DEVICE FOR CLEANING THE ELECTRODE SECTION OF AN IGNITION PLUG Sheet .2 of 3 Filed Dec. 21, 1966 m T N E V m 1 April 1,1969

RYOICHI MORI DEVICE FOR CLEANING THE ELECTRODE SECTION OF AN IGNITION PLUG Sheet Filed Dec. 21, 1966 FIG.6

INVENTOR.

United States Patent 3,435,561 DEVICE FOR CLEANING THE ELECTRODE SECTION OF AN IGNITION PLUG Ryoichi Mori, Tokyo, Japan, assignor to Nikko Denki Kogyo Kabushiki Kaisha, Tokyo, Japan Filed Dec. 21, 1966, Ser. No. 603,661 Int. Cl. B24c 3/00 U.S. Cl. 51-8 4 Claims ABSTRACT OF THE DISCLOSURE A device for cleaning the electrode section of an ignition plug. The device has upper and lower cavity sections with an annular partition separating them. A spark plug is adapted to be placed in the partition wall with a portion of the electrode section exposed in the upper cavity section, with the remainder of the spark plug in the lower section. A measured amount of abrasive material is placed in the upper cavity section and a compressed air nozzle extends through the cover of the upper section for injecting air into the upper section for agitating the abrasive material for cleaning the electrode section.

The present invention relates to an improved cleaning device, and more particularly to a novel and improved device suitably employed for cleaning the electrode section of an ignition plug to be mounted in an internal combustion engine or the like.

Usually, when a conventional ignition plug is mounted in an internal combustion engine and the engine is continuously operated for along period of time, a portion of the fuel very often remains in an incompletely burned state and carbon is freed from the incompletely burned fuel portion which will eventually deposit on and adhere to the elements in the electrode section of the ignition plug. And the elements in the electrode section of the conventional ignition plug are often caused to oxidize due to high temperature heat generated at the time of the ignition of an internal combustion engine in which the ignition plug is mounted and accordingly, the value of discharge resistance between the electrodes in the electrode section will become high resulting in lowering the efficiency of the ignition plug to a considerable degree.

Therefore, one object of the present invention is to provide a novel and improved cleaning device for the electrode section of an ignition plug which can easily and positively remove the free carbon, oxide and the like which have deposited on and adhered to the elements in the ignition plug electrode section.

Another object of the present invention is to provide a novel and improved cleaning device for the electrode section of an ignition plug which is compact in construction, convenient for carrying about and easy to handle.

Another object of thepresent invention is to provide a novel and improved cleaning device for the electrode section of an ignition plug which can perform the cleaning operation hygienically.

A further object of the present invention is to provide a novel and improved cleaning device for the electrode section of an ignition plug which is inexpensive to manufacture and substantially free from trouble.

When one cycle of a cleaning operation is carried out on the electrode section of an ignition plug by the use of the cleaning device constructed in accordance with the present invention for the purpose of removing the free carbon, oxide and the like which have deposited on and adhered to the elements in the electrode section of the ignition plug, prior to the initiation of the operation proper, a predetermined amount of abrasive material is first charged into the cleaning operation or upper cavity 3,435,561 Patented Apr. 1, 1969 ice section of the main body of the cleaning device and the upper cavity section is sealed 01f, and then an ignition plug whose electrode section is to be cleaned is inserted into the lower cavity section of the main body at the open lower end thereof until the upper portion of the plug electrode section is positioned in a predetermined position at the bottom of the upper cavity section. Thereafter, the first stage in the cleaning operation is initiated by supplying compressed air from any conventional compressed air supply means through an air injection nozzle extending down into the upper cavity from above so as to cause the compressed air to swirl within the upper cavity section. Thereby the abrasive material which has deposited at the bottom of the upper cavity is stirred and also caused to swirl during the swirling movement of the compressed air which entrains the abrasive material therein and the stirred and swirling abrasive material can strike against and abrade the elements in the electrode section to efficiently remove a substantial portion of the deposited and adhered free carbon, oxide and the like from the elements in the electrode section of'the ignition plug in a brief period of time. After having stirred and swirled the abrasive material, the compressed air injected through the nozzle is filtered by means of a filtering medium mounted on the inner wall of the upper cavity section before the air is discharged out of the cavity section to the atmosphere whereby the possibility of pollution of the atmospheric air with dust and other fine particles which would otherwise be dispersed into the atmosphere by the discharged carrier gas. Therefore, the novel cleaning device is satisfactory from a hygienic point of 'view.

After the deposited and adhered substance removing first stage operation by the abrasion action in the man ner as mentioned above, when the cleaning device is turned upside-down with the ignition plug electrode section still being positioned in the above-mentioned predetermined position at the bottom of the upper cavity section, the abrasive material which now is at the bottom of the upper cavity section is caused to fall down and be deposited on the inner side of the top cover of the upper cavity section of the cleaning device in its upside-down position and the leading end of the injection nozzle which extends through the top cover is caused to project above the level of the abrasive material which is now on the inner side of the cover. Therefore, when compressed air is injected from the compressed air supply means through the injection nozzle in this position of the cleaning device, only the compressed air is blown against the elements in the plug electrode section so as to remove the remainder of the deposited and adhered carbon, oxide and the like which have been left unrernoved during the initial abrasive operation stage whereby the plug electrode can be easily and positively cleaned. The thus cleaned plug electrode section can again perform its function satisfactorily after removing the plug from the mounting position in the cleaning device and replacing it with a dirty plug.

The novel cleaning device for the electrode section of an ignition plug includes no expensive moving parts, is inexpensive to manufacture, substantially free from trouble, compact in construction and convenient for carrying about. Furthermore, since the change-over from the compressed air and abrasive material blowing operation to the compressed air blowing operation only and vice versa can be performed by simply turning the cleandevice upside-down, the handling of the cleaning device is quite simple.

According to the present invention, there is provided a device for cleaning the electrode section of an ignition plug, which comprises in combination a hollow cylindrical main body having an upper cavity section and a lower cavity section separated by an annular partition wall, said upper cavity section having a bored bottom for exposing said electrode section of the ignition plug to be subject to cleaning operation and said lower cavity section being adapted to receive the remainder of said ignition plug during said cleaning operation; a measured amount of abrasive material partially filling said upper cavity section and normally deposited at the bottom of said upper cavity section; an annular holding member removably received in said annular partition wall below said upper cavity section for removably holding said electrode section of the ignition plug therein; a bored closure cover removably mounted on the top of said upper cavity section; a compressed air injection nozzle extending down through said bore in the closure cove-r from above and fixedly secured to the cover, the lower or leading end of said nozzle opposing said annular holding member at a predetermined distance from the top end of the holding member; and an annular filtering medium extending along the inner wall of said upper cavity section for filtering the compressed air injected through said injection nozzle, and in which when said cleaning device is turned upside-down, said abrasive material which is now at the bottom of said upper cavity section is caused to fall onto the inner side of said closure cover and said leading end of the injection nozzle is caused to project above the upper surface of the abrasive material which has been deposited on the inside of the cover.

The above and other objects and advantages of the present invention will be more readily apparent from the following description when read in conjunction with the accompanying drawings in which:

FIG. 1 is a vertical sectional view of a preferred form of cleaning device for the electrode section of an ignition plug constructed in accordance with the present invention;

FIG. 2 is a top plan view of said cleaning device for the electrode section of the ignition plug of FIG. 1;

FIG. 3 is a bottom plan view of said cleaning device for the electrode section of the ignition plug of FIG. 1;

FIG. 4 is a cross-sectional view taken substantially along the line IVIV of FIG. 1;

FIG. 5 is a fragmentary vertical sectional view on an enlarged scale which shows the manner in which the abrasive material measuring member is mounted in said cleaning device;

FIG. 6 is a vertical sectional view of a modified form of cleaning device for the electrode section of an ignition plug constructed in accordance with the present invention;

FIG. 7 is a bottom plan view of the air distributor member provided at leading end of the nozzle of said modified form of cleaning device of FIG. 6;

FIG. 8 is a fragmentary vertical sectional view of the upper end portion of an ignition plug which is to be cleaned by any of said different forms of cleaning devices as shown in the preceding FIGS; and

FIG. 9 is a top plan view of said ignition plug of FIG. 8.

Referring now to the accompanying drawings, and more particularly to FIG. 1 thereof in which a preferred form of cleaning device for the electrode section of an ignition plug according to the present invention is shown with an ignition plug which is to be cleaned by the cleaning device in position therein, the ignition plug being shown in chain lines. As shown in FIG. 1, the cleaning device generally comprises a main body 10 in the form of a hollow cylinder and the interior of the main body is divided into the upper cavity section 12 and lower cavity section 13 by means of an annular partition wall 11 which extends along the inner periphery of the main body and projects inwardly from the inner periphery toward the longitudinal axis of the main body. The upper surface of the partition wall 11 is tapered toward the vertical axis of the main body 10 in such a manner that the upper surface thereof defines a funnel shape 12' which serves as the bottom wall of the upper cavity section 12. The bottom wall 12' of the upper cavity section 12 has a center bore 14 formed therein and a large diameter female-threaded bore 15 is formed in the bottom surface of the partition wall 11 which is in communication with the center bore 14 of the bottom wall 12' of the upper cavity section 12. The peripheral wall of the upper cavity section 12 is provided with a plurality of small bores 12a arranged in an equally spaced relation to each other along both the periphery and height of the upper cavity section 12. An annular filter element or medium 16 is provided along the inner peripheral surface of the upper cavity section 12 and is held against the inner peripheral surface by means of a plurality of sector rings 17 each having a plurality of small holes therein (FIG. 4).

The upper cavity section 12 also has a removable cover 18 having a reversed cup-shape screwed over the top thereof and the cover has a center opening 18' through which a compressed air injection nozzle 19 extends and is fixedly held in position therein. Thus, when the cover 18 is screwed onto the top of the upper cavity section 12 and the section is sealed at the top end, the leading or lower end of the nozzle 19 is disposed above the center bore 14 in the bottom wall 12 of the upper cavity section 12 in an opposed and spaced relation with respect to the bore 14 while the opposite or upper end of the nozzle which projects upwardly of the top of the upper cavity section 12 is adapted to be connected to an air hose (not shown) of any conventional air compressor (not shown) which is conventionally used to supply compressed air to a pneumatic tire.

An ignition plug holding member 20 having a femalethreaded bore 21 in the center and a male thread 21a on the outer periphery is removably received in the femalethreaded bore 15 in the partition wall 11 for holding the electrode section of an ignition plug to be cleaned by the cleaning device during the cleaning operation. Thus, when the holding member 20 is disposed in the position within the female-threaded bore 15 as shown in FIG. 1 by threaded engagement with the partition wall 11, the center bore 21 of the holding member 20 is axially aligned with the center bore 14 of the bottom wall 12 of the upper cavity section 12. The partition wall center bore 21 is provided on the inner peripheral surface in the upper portion of the bore with an annular projection or shoulder 2112 which serves as a stop means against which the fore or upper end of the electrode section of the ignition plug will abut when the plug is screwed into the partition wall bore 21 whereby the ignition plug can be easily and positively positioned in the cleaning device when the plug is being subject to the cleaning operation by the cleaning device. The ignition plug holding member 20 is further provided on the bottom surface with an annular recess 22 into which a spanner (not shown) is adapted to be inserted for screwing the holding member 20 into and out of the bore 21. It is to be understood that by providing several ignition plug holding members having center threaded bores 21 of different diameters, the novel cleaning device can be suitably employed for cleaning ignition plugs having different diameters.

In FIG. 5, reference numeral 23 generally designates a removable material measuring member which also serves as a sealing means for the center bore 14 in the bottom wall 12 of the upper cavity section 12. The abrasive material measuring member 23 generally comprises a larger diameter or upper rod section 23a and an integral smaller diameter or lower rod section 23b which is axially aligned with the larger diameter section. It should be understood that when the smaller diameter rod section 2312 is employed, that is, when the second holding member 20' is employed for holding a smaller diameter ignition plug which is to be cleaned, the abrasive material member 23 should be turned upside-down so as to dispose the smaller diameter rod section on the top. It should be also understood that before the cleaning operation proper is initiated,

the abrasive material measuring member is removed from the main body of the cleaning device. The outer periphery of the larger diameter rod section 23a is provided on the lower end portion with a male thread 24a which is adapted to engage the center threaded bore 21 of the holding member 20 while the smaller diameter rod section 23b is provided in the outer periphery of the upper end portion with a male thread 24b which is adapted to engage the female-threaded center bore 21 having a diameter smaller than that of the bore 21 of the member 20 and formed in a dilferent type of holding member 20' which is to be employed for cleaning a smaller diameter ignition plug as will be explained hereinafter. Each of the larger and smaller diameter rod section 23a and 23b is provided on its outer periphery with a graduation 25a and 25b, respectively. The inner female threaded bore 21' of the second holding member 20 having an outer thread 21'a extends from the upper end and terminates short of the lower end of the associated holding member whereby an inner annular projection or shoulder 2177 is formed in the upper end portion of the holding member against which the adjacent end of the male thread portion 24b can abut. The adjacent end of the male thread portion 24a of the larger diameter rod section 23a can also abut against the inner annular projection or shoulder 21b of the first or larger diameter holding member 20. Thus, when the abrasive material measuring member 23 is screwed into the larger or smaller diameter holding member 20- or 20 which is selected depending upon the diameter of the ignition plug to be cleaned by the novel cleaning device until the leading end of either the male thread portion 24a or 24b of the larger or smaller diameter rod section 23a or 23b abuts against the annular shoulder 21b or 21'b, the larger or smaller diameter rod section 23a or 23b extends into the upper cavity section 12 of the main body 10 of the cleaning device to a predetermined distance. In this case, the leading end of the nozzle 19 is received within the recess formed at the adjacent end face of either the larger diameter or smaller diameter rod section 23a or 23b whereby the projection of either the larger or smaller diameter rod section into the upper cavity section 12 will not be obstructed.

When the above-mentioned novel cleaning device is operated for cleaning the electrode section 29 of an ignition plug 26, either the first holding member 20 having the larger diameter female threaded center bore 21 or the second holding member 20 having the smaller diameter female threaded center bore 21' is first selected depending upon the diameter of the electrode section 29 of the ignition plug 26. Although the operation of the novel cleaning device will be he-reinbelow explained in connection with an instance in which the holding member 20 having the larger diameter threaded center bore 21 is employed, it is to be understood that the same will also apply to an instance in which the other type holding mem ber 20 having the smaller diameter threaded center bore 21' is employed for the same purpose. Prior to the initiation of the cleaning operation proper the holding member 20 is first screwed into the female-threaded bore in the partition wall 11 and then the abrasive material measuring member 23 is screwed into the holding member by means of its outer peripheral male thread 24a on the larger diameter rod section 23a and the femalethreaded center bore 21 of the holding member 20. Thereafter, powdery abrasive material 2 7 such as Carborundum is charged into the upper cavity section 12 of the main body 10 through the open top thereof which is not yet closed by the cover 18 at this stage of the operation. After the abrasive material 27 has been charged into the upper cavity section 12 in a predetermined amount which is determined by a selected reading on the graduation a, the cover 18 is screwed onto the top of the main body 10. The covered and sealed cleaning device is then turned upside-down and the measuring member 23 is screwed out of the holding member 20 by means of any suitable tool which can be inserted into the open lower end of the lower cavity section 13. In place of the measuring member 23, the ignition plug 26 is then screwed into the holding member 20 until the top end of the threaded upper portion 28 on the electrode section 29 of the plug abuts against the inner shoulder 21b of the holding member 20 whereby the upper portion of the electrode section 29 of the ignition plug 26 is positioned within the center bore 14 of the bottom wall 12 of the upper cavity section 12 of the cleaning device main body 10 and the remaining portion of the electrode section 29 and the body of the ignition plug 26 is housed within the lower cavity section 13 of the cleaning device main body.

After the ignition plug 26 has been properly positioned within the main body 10 by means of the holding member 20, the cleaning device is again turned upside-down to the original position. Then, the upper end of the nozzle 19 is connected to the air hose (not shown) of an air compressor (not shown) and compressed air is supplied from the compressor through the nozzle 19 into the upper cavity section 12 of the cleaning device main body 10. The thus supplied air is injected against the abrasive material 27 which has been deposited at the lower portion of the funnel shape bottom wall 12' of the upper cavity section 12 so as to cause the abrasive material to swirl within the upper cavity section 12. The abrasive material 27 applies abrasive action to the electrode section 29 of the ignition plug 26 while the material is swirling whereby a substantial amount of carbon, oxide and the like which have deposited on and adhered to the elements of the electrode section 29 can be effectively removed from the electrode section elements.

As the cleaning operation is being carried out, the supplied compressed air itself is permitted to escape from the upper cavity section 12 through the small bores in the sector ring 17 and the pores of the filtering medium which removes the dirt and other fine particles contained in the air therefrom 16 into the atmosphere. However, the abrasive material 27 entrained in the swirling air is prevented from being discharged from the cleaning device.

After the abrasive applying stage in the cleaning operation by the novel cleaning device has been completed, the supply of the compressed air is temporarily interrupted and the cleaning device is turned upside-down so as to cause the abrasive material 27 to be deposited on the inside of the cover 18 with the leading end portion of the nozzle 19 projecting above the upper surface of the abrasive material deposit. With the abrasive material 27 and the leading end of the nozzle '19 positioned as mentioned just above, when the air compressor is again actuated so as to supply compressed air through the noz zle 19 into the upper cavity section 12 of the cleaning device main body 10, only the compresed air is blown against the elements in the electrode section 29 of the ignition plug 2 6 and the remaining carbon, oxide and the like which have been left on the elements of the electrode section 29 during the initial abrasive applying stage in the cleaning operation can be effectively blown off the elements whereby the electrode can be completely cleaned.

It should be understood that a portion of the abrasive material 27 used during the abrasive applying stage may remain on the electrode elements even after the cleaning device has been turned upside-down as mentioned just above, but such portion of the abrasive material can be removed from the electrode elements during the last stage or exclusive air blowing stage.

When the electrode section of an ignition plug having the same diameter as the previously cleaned ignition plug is desired to be cleaned in succession to the cleaning operation on the previous ignition plug, the already cleaned ignition plug is screwed off the holding member 20 and the new ignition plug is screwed into the holding member 20 in place of the removed plug with the cleaning device maintained in its upside-down position in which the abrasive material 27 is deposited on the inside of the cover 18 and the leading end portion of the nozzle 19 projects above the upper surface of the abrasive material deposit as mentioned above. Thereafter, the procedure mentioned in connection with the cleaning of the first ignition plug may be repeated for the new ignition plug.

When the novel cleaning device is not used and is desired to be stored ready for future use, the cleaning device may be stored with the holding member 20 or 20, in which the larger diameter rod section 23a or smaller diameter section 23b of the measuring member 23 is in threaded engagement, being in threaded engagement in the threaded bore 15 in the partition wall 11 whereby loss of these component elements can be prevented.

FIG. 6 illustrates a modified embodiment of cleaning device constructed in accordance with the present invention. This modified embodiment is substantially the same as the preceding embodiment except that in this modified embodiment, the nozzle 19' has at its lower or leading end a reversed cup-shaped air distributing member 30 threaded thereon and the cup-shaped member has a circular bottom 30' having a plurality of equal angularly spaced bores 31 (three bores in the illustrated embodiment) formed therein as shown in FIG. 7. The positions of these bores 31 correspond to those of bores 29e formed in the annular recess defined by the insulator 29b sur rounding the center electrode 29a and the housing 29d of the electrode section 29 of the ignition plug 26 to be cleaned, (FIGS. 7, 8 and 9).

Although the construction of the electrode section 29 of the ignition plug 26 itself does not form part of the present invention, for the purpose of better understanding of the present invention the construction of the plug electrode section 29 will be briefly explained referring to FIGS. 8 and 9 of the accompanying drawing. As shown in these figures, the electrode section 29 generally comprises a center electrode 29a, a coaxial insulator 29b disposed around the center electrode, a ground electrode 290 extending transversely over the center electrode 29a and insulator 29b and integral with a hollow cylindrical housing 29d which houses the center electrode 29a and insulator 29b therein. The insulator 29b and housing 29d define an annular recess therebetween and the annular recess is formed with three equally angular spaced vertical bores 29e therein and as mentioned above, these vertical bores 29e communicate with the three bores 31 formed in the bottom 30' of the cup-shaped air distributing member 30, respectively. As seen in the vertical sectional view of FIG. 8, the annular recess and these vertical bores 29e taper toward their bottoms, respectively.

In the operation of the modified embodiment of cleaning device of the present invention, the preparatory procedure is substantially the same as that explained in connection with the first embodiment of FIGS. 1 through except that the reversed cup-shaped air distributing member 30 is screwed onto the lower end of the nozzle 19 and then, the cover 18 is screwed onto the top of the main body of the cleaning device. Following the preparatory procedure the cleaning operation proper is initiated by injecting compressed air from the air compressor through the nozzle 19 and the cup-shaped air distributing member which divides the air flow into three equally spaced air streams by means of the three bores 31 formed in the bottom 30 thereof. The air streams can reach deep into the bottoms of the three tapered bores 29e in the annular recess defined by the insulator 29b and housing 29d whereby the bores 29e as well as the other elements of the electrode section 29 can be more effectively abraded and cleaned. This modified embodiment is more advantageous than the first embodiment because when the compressed air is injected through only the nozzle 19 toward the electrode section 29 or the air is injected in a single stream in the first embodiment, the single air stream may hit against only narrow localized areas on the ground electrode 29c and insulator 29b and there is the possibility of excessive abrasion of these localized areas on the elements while the use of the air flow distributing member 30 having the plurality of bores 31 of the second embodiment makes it possible to evenly distribute the compressed air over a wider area of the electrode elements by means of the plurality of bores 31 whereby the disadvantage inherent in the single air stream embodiment can be eliminated.

Furthermore, by provision of different air distributing members 30 having air flow distribution bores 31 which are different in size, number and arrangement, respectively, these different air distributing members 30 can be selectively employed depending upon the type and diameter of the ignition plug to be cleaned.

While two preferred embodiments of the invention have been shown and described in detail it will be understood that they are for the purpose of illustration only and are not to be taken as a definition of the scope of the invention, reference being had for this purpose to the appended claims.

What is claimed is:

1. A device for cleaning the electrode section of an ignition plug which comprises a hollow cylindrical main body having an upper cavity section and a lower cavity section and an annular partition wall separating said cavity sections; said upper cavity section having a bore in the bottom thereof for receiving a portion of the electrode section of a plug and adapted to expose a portion of the electrode section to be subject to the cleaning operation and said lower cavity section being adapted to receive the remaining portion of said ignition plug; a measured amount of abrasive material partially filling said upper cavity section and normally deposited at said bottom of the upper cavity section; an annular holding member removably received in said annular partition wall below said upper cavity section bottom for removably holding the electrode section of a plug therein; a bored closure cover removably mounted on the top of said upper cavity section; a compressed air injection nozzle extending down through said bore in the closure cover and fixedly secured to the cover, the lower end of said nozzle being opposed to said holding member at a predetermined distance from the top of the holding member; and an annular filtering medium extending along the inner periphery of said upper cavity section, whereby when said cleaning device is turned upside-down, said abrasive material is deposited on the inner side of said closure cover and said leading end of the nozzle projects above the upper surface of the abrasive material deposit.

2. A device for cleaning the electrode section of an ignition plug as claimed in claim 1 in which said leading end of the compressed air injection nozzle has a reversed cup-shaped air distributing member screwed thereon and said air distributing member has a bottom having a plurality of air distributing through bores therein, the number and arrangement of said plural air distributing bores corresponding to bores formed in the insulator for the center electrode of the electrode section of the plug to be cleaned.

3. A device for cleaning the electrode section of an ignition plug as claimed in claim 1 further comprising an abrasive material measuring member having a pair of integral rod sections removably received in said electrode section holding member vertically extending through a substantial portion of said main body of the cleaning device for closing said bores formed in the upper cavity section bottom, and annular holding member respectively, said measuring member being provided on the outer peripheries of said rod sections with graduations for measuring the amount of said abrasive material to be charged into said upper cavity section.

4. A device for cleaning the electrode section of an ignition plug which comprises a hollow cylindrical main body having an upper cavity section, a lower cavity section and an annular partition wall between said upper and lower cavity sections, and having a center bore therein for receiving a portion of said electrode section of an ignition plug and adapted to expose the electrode section to be subject to the cleaning operation and said lower cavity section being adapted to receive the remaining portion of said ignition plug; an annular holding member removably received in said bore in the partition Wall below said upper cavity section for removably holding the electrode section and exposing the electrode section to be subject to the cleaning operation; a bored closure cover removably mounted on the top of said upper cavity section; a compressed air injection nozzle extending down through said bore in the closure cover, the lower end of said nozzle being opposed to said holding member and at a predetermined distance from the top of the holding member; and an annular filtering medium extending along the inner periphery of said upper cavity section; whereby when a measured amount of abrasive material is placed in said upper cavity section partially filling it and then said cleaning device is turned upside down, said abrasive material is deposited on the inner side of said closure cover and said leading end of the injection nozzle projects above the upper surface of the abrasive material deposit.

References Cited UNITED STATES PATENTS 1,292,004 l/ 1919 Miller 51-8 1,399,225 12/ 1921 Pellet 51-8 1,421,001 6/ 1922 Hagen 5 l--8 1,864,072 6/ 1932 Kleinfeld 51-8 1,867,324 7/1932 Mullan 518 LESTER M. SWINGLE, Primary Examiner. 

